package com.gl.basis.common.util;

import java.util.Random;

public class RandomUtil {
	private static String characterEncoding = "UTF-8";
	public static final String ALLCHAR = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";  
    public static final String LETTERCHAR = "abcdefghijkllmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";  
    public static final String NUMBERCHAR = "0123456789";
    public static final String NUMBERCHARNOZERO = "123456789";
  
    /** 
     * 返回一个定长的随机字符串(只包含大小写字母、数字) 
     *  
     * @param length 
     *            随机字符串长度 
     * @return 随机字符串 
     */  
    public static String generateString(int length) {  
        StringBuffer sb = new StringBuffer();  
        Random random = new Random();  
        for (int i = 0; i < length; i++) {  
            sb.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));  
        }  
        return sb.toString();  
    }  
    
    /** 
     * 返回一个定长的随机字符串(只包含大小写字母、数字) 
     *  
     * @param length 
     *            随机字符串长度 
     * @return 随机字符串 
     */  
    public static String generateNumberString(int length) {  
        StringBuffer sb = new StringBuffer();  
        Random random = new Random();  
        for (int i = 0; i < length; i++) {  
            sb.append(NUMBERCHAR.charAt(random.nextInt(NUMBERCHAR.length())));
        }  
        return sb.toString();  
    }  
    
    /** 
     * 返回一个定长的随机字符串(只包含大小写字母、数字) 
     *  
     * @param length 
     *            随机字符串长度 
     * @return 随机字符串 
     */  
    public static String generateNumberStringNonzero(int length) {  
        StringBuffer sb = new StringBuffer();  
        Random random = new Random();  
        for (int i = 0; i < length; i++) {  
        	 sb.append(i==0?(NUMBERCHARNOZERO.charAt(random.nextInt(NUMBERCHARNOZERO.length()))):(NUMBERCHAR.charAt(random.nextInt(NUMBERCHAR.length()))));
        }  
        return sb.toString();  
    }  
    
    public static int generateNumberNonzero(int length) {  
        return Integer.parseInt(generateNumberStringNonzero(length));  
    }
    /** 
     * 返回一个定长的随机纯字母字符串(只包含大小写字母) 
     *  
     * @param length 
     *            随机字符串长度 
     * @return 随机字符串 
     */  
    public static String generateMixString(int length) {  
        StringBuffer sb = new StringBuffer();  
        Random random = new Random();  
        for (int i = 0; i < length; i++) {  
            sb.append(ALLCHAR.charAt(random.nextInt(LETTERCHAR.length())));  
        }  
        return sb.toString();  
    }  
  
    /** 
     * 返回一个定长的随机纯大写字母字符串(只包含大小写字母) 
     *  
     * @param length 
     *            随机字符串长度 
     * @return 随机字符串 
     */  
    public static String generateLowerString(int length) {  
        return generateMixString(length).toLowerCase();  
    }  
  
    /** 
     * 返回一个定长的随机纯小写字母字符串(只包含大小写字母) 
     *  
     * @param length 
     *            随机字符串长度 
     * @return 随机字符串 
     */  
    public static String generateUpperString(int length) {  
        return generateMixString(length).toUpperCase();  
    }  
  
    /** 
     * 生成一个定长的纯0字符串 
     *  
     * @param length 
     *            字符串长度 
     * @return 纯0字符串 
     */  
    public static String generateZeroString(int length) {  
        StringBuffer sb = new StringBuffer();  
        for (int i = 0; i < length; i++) {  
            sb.append('0');  
        }  
        return sb.toString();  
    }  
  
    /** 
     * 根据数字生成一个定长的字符串，长度不够前面补0 
     *  
     * @param num 
     *            数字 
     * @param fixdlenth 
     *            字符串长度 
     * @return 定长的字符串 
     */  
    public static String toFixdLengthString(long num, int fixdlenth) {  
        StringBuffer sb = new StringBuffer();  
        String strNum = String.valueOf(num);  
        if (fixdlenth - strNum.length() >= 0) {  
            sb.append(generateZeroString(fixdlenth - strNum.length()));  
        } else {  
            throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth  
                    + "的字符串发生异常！");  
        }  
        sb.append(strNum);  
        return sb.toString();  
    }  
  
    /** 
     * 每次生成的len位数都不相同 
     *  
     * @param param 
     * @return 定长的数字 
     */  
    public static int getNotSimple(int[] param, int len) {  
        Random rand = new Random();  
        for (int i = param.length; i > 1; i--) {  
            int index = rand.nextInt(i);  
            int tmp = param[index];  
            param[index] = param[i - 1];  
            param[i - 1] = tmp;  
        }  
        int result = 0;  
        for (int i = 0; i < len; i++) {  
            result = result * 10 + param[i];  
        }  
        return result;  
    } 
    
    /**
     * 获取随机字符串
     * @return
     */
    public static String getNonceStr() {
		Random random = new Random();
		return Md5Utils.encode(String.valueOf(random.nextInt(10000)));
	}
    
    /**
     * 获取指定范围的随机数,从0开始
     * @param min
     * @param max
     * @return
     */
    public static int getRandom(int max) {
    	Random random = new Random();
        return random.nextInt(max);
    }
    
    /**
     * 获取指定范围的随机数
     * @param min
     * @param max
     * @return
     */
    public static int getRandom(int min,int max) {
    	Random random = new Random();
        return random.nextInt(max) % (max - min + 1) + min;
    }
  
}
